Stabilization of aqueous BaTiO₃ suspensions with ammonium salt of poly(acrylic acid) at various pH values

Ammonium salt of poly(acrylic acid) (PAA-NH₄) has been used to stabilize aqueous BaTiO₃ suspensions at various pH values. Adsorption of PAA-NH₄ causes the zeta potential to become more negative, although this effect becomes less dramatic as the pH increases. The concentration of PAA-NH₄ required to stabilize aqueous BaTiO₃ suspensions decreases with increasing pH. The critical amount of PAA-NH₄ as a function of pH is plotted in a stability map, as determined by adsorption, rheology, and sedimentation studies.